Most of the energy that generated the most powerful geomagnetic storm of this solar cycle on March 17-18, 2015 came from this fast-moving,
Earth-directed coronal mass ejection (CME) on March 15, 2015. The CME, associated with a relatively moderate, M-class flare, impacted
geospace in combination with a high-speed solar wind stream from a coronal hole. The action originated in a solar magnetic active
region on the earthward-facing side of the Sun.

The first movie shows the event in a combination of the Sun (in extreme UV light from the Solar Dynamics Observatory) and the expanding
cloud of particles observed by the two SOHO LASCO visible light coronagraphs, and covers just over a day of activity. The second movie
shows a close-up of the event as observed by SOHO's LASCO C2 coronagraph. The geomagnetic storm triggered spectacular aurorae, which were visible from countries as far south as Hungary and Austria in Europe and many of the lower 48 US states.

SOHO began its Weekly Pick some time after
sending a weekly image or video clip to the American Museum of Natural
History (Rose Center) in New York City. There, the SOHO Weekly Pick is
displayed with some annotations on a large plasma display.

If your institution would also like to receive the same Weekly Pick from us
for display (usually in Photoshop or QuickTime format), please send
your inquiry to steele.hill@gsfc.nasa.gov.